For many surface and subsea oil and gas wells, a series of pipes, fittings, valves, and gauges are used on a wellhead to control the flow and achieve well completion. A Christmas or production tree is generally attached to the wellhead and the pipes, fittings, valves and gauges are typically routed and connected to the tree. One, or a plurality of, penetrators or stems, may be installed in a Christmas tree to engage components installed within the wellhead, such as a tubing hanger. The penetrators may be horizontal, vertical, or at other angles, and allow downhole control lines, such as electrical and/or hydraulic, to be routed through the tree and tubing hanger sidewalls and be routed down to components below the wellhead.
Subsea horizontal tree tubing hangers generally utilize a sealing arrangement for control lines that rely on the weight of completion tubing to activate the device sealing mechanism. On conventional surface wellhead applications, however, there is insufficient space available on most completions to incorporate this sealing arrangement
Well completions are now using an increasing number of downhole control lines with some operators now requesting up to eleven separate control lines. As explained above, the conventional method of exiting a plurality of control lines through the wellhead usually requires that the control line pass through a tubing hanger in a continuous manner and then exit through the wellhead body. However, large numbers of control lines make this conventional exit arrangement complex and difficult to complete within the limited space available in the wellhead upper bowl area. Fitting multiple control lines in the limited space currently available is difficult and labor intensive, with control lines frequently bent in awkward directions with some having to physically cross over others. Control lines are thus frequently damaged. Thus, little space on this particular completion arrangement is left to provide “spare” length on the control line.
Further, if any problems are encountered during the control line termination phase through the wellhead, it may be necessary to pull the completion, which is an expensive and time-consuming exercise involving significant rig down-time.
A need exists for a technique to allow sufficient clearance for a plurality of downhole control lines at a well.